JAMB - Physics (2005 - No. 12)
A silicon material is dopped with an element of a certain group and an n-type semi-conductor is formed. the most likely group of the element is
V
III
I
II
Explication
Silicon is a tetra valent (4 valent) element, and in order to produce an n type semi-conductor, it has to be dropped with a penta valent (5valent)element, that, that is element in group five (v)